Friction element



Oct. 22, 1940. A. B. KEMPEL FRICTION ELEMENT Filed July 7, 19:59

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Patented Oct. 22, 1940 UNITED STATES 2,218,689 FRICTION ELEMENT ArthurB. Kempel, East Brady, Pa., assignor to Rex-Hide, Incorporated, EastBrady, Pa, a corporation of Pennsylvania Application July '7,1939,,Serial No. 283,236

2 Claims. (Cl. 188-234) I This invention relates to elements of frictioncouplings including brakes and analogous struc-. tures such as clutches.Its object is to provide an improved connection between the foundationmember of such an element and the facing of friction material. r

Brake shoes including a body or foundation member and a friction facingsuitably attached thereto, as by riveting, are frequently kept instorage for a considerable time after assembling, before being installedin the brakes. During that time they are aptto deteriorate, as byrusting of the attaching face of the steel shoe body, re-

sulting in an imperfect joint. Attempts have- 15 been made to improvethe joint by employing a cementing layer, such as rubber cement, thesolvent of which very quickly evaporates, leaving a tough and usuallyirregular layer of rubber which prevents proper seating of the lining,so that such cementsii ave been unsatisfactory.

The present invention provides a moisture-retaining, water-solublecementing layer between the shoe body and friction layer,-preferablycomposed principally of sodium silicate or water glass, together with afiller of clay or other earthy material, which will flow easily whenapplied and retain its moisture for along time;

When the shoe is put in service, the lining will properly seat itself onthe shoe body or founda- 80 tion member and the cementing layer willharden by drying out through the frictional braking heat and become veryhard according to a well-known property of sodium silicate cements, notpreviously utilized in friction elements so far as I am aware. A perfectwatertight and oil-proof joint 35 is thereby obtained between the shoebody and the friction facing, and the rivets or other mechanicalfastenings are also firmly anchored so that they not readily work loose.

Of the accompanying drawing,

40 Fig. 1 is a side elevation of a brake shoe made according tomyinvention.

Fig. 2 is an enlarged transverse section on the line 2-2 of Fig. 1.

In the drawing, Ill is the metallic brake shoe 4 body or foundationmember, of the usual arcuate form and T-shaped cross section, II is theouter layer of molded or woven friction material, usuallyincludingasbestos and a binder, and l2, II are metallic rivets attaching saidfacing or brake lining to the shoe body, said rivets having their outerheads in countersunk holes l3 in the lining and their stems extendingthrough holes I 4 in the parts.

foundation member,

' friction heat of braking.

I5 is a cementing layer interposed between the shoe body ill and thefriction lining or facing H and adapted to surround the rivet stems inthe holes, M. This cementing layer is of the nature previouslyindicated, consisting mainly of a thick 5 water solution of sodiumsilicate in major proportion, such. as two thirds or more, and theremainder mainly an earthy filler, such as a soft clay, the compositionbeing free-flowing and readily spreadable upon the surface to be coated.There are alarge number of compositions known in the art of sodiumsilicate cements, including various kinds of clay fillers or substitutessuch as whiting, etc., and adapted to be more or less diluted withwater. Most of them will suit the present purpose.

The cementing layer l5 of sodium'silicate solution and filler, whenplaced between the shoe body l0 and the friction lining H, has theproperty of retaining its moisture for a long periodof 2 time, withoutdrying out until put in service. When the brake shoe is installed andsubjected to the heat of braking friction, such heat rapidly expels themoisture from the layer IS, the braking pressure, by reason of thefluent nature of the cementing layer, causes the lining H' to seatproperly against the shoe body III and embeds the rivets II in thecrevices or clearances of the holes ll surrounding .therivet stems,whereby the cementing layer becomes permanently hardened to effect aperfect bond. between the shoe body and lining and effectively anchorthe rivets l2 against loosening in service.

The shape of the friction element is not confined to an arcuate form butmay be anything s usual in brake shoes or clutch plates, and thedescribed details of embodiment could be otherwise varied within thescope of my invention.

I claim: V

1. A friction element comprising a metallic a facing layer of frictionmaterial secured thereto by mechanical fasteners, and an interposedcementing and fastener-anchoring layer of water-soluble, siliceous andearthy filler material which is hardenable by the 2. A brake shoecomprising a metallic foundation member, a facing layer of frictionmaterial secured thereto by rivets, and an interposed cementing andrivet-anchoring layer of heat-hard- 'ening material which is principallysodium silicate.

ARTHUR B.

